99 Percentile Qs Bank for JEE MainPhysicsLaws of Motion
An insect crawls up a hemispherical surface very slowly (see the figure). The coefficient of friction between the insect and the surface is 1/3. If the line joining the centre of the hemispherical surface to the insect makes an angle α with the vertical, the maximum possible value of α is given by
Options
- Acot α = 3
- Btan α = 3
- Csec α = 3
- Dcosec α = 3
Correct answer
A. cot α = 3
Step-by-step solution
For not to slip μ N ≥ mg  sin  α μ mg cos  α = mg  sin  α cot  α = 1 μ       ⇒      cot  α = 3